Homebrew PCBs

Hi guys.

I just dumped the contents of my 2-litre concertina bottle of FeCl3 into 
my etching tank, and about half way through I was treated to a loud 
HISSSSS as this lot got dumped in the funnel:

http://groups.yahoo.com/group/Homebrew_PCBs/photos/album/338698001/pic/1053817307/view

Basically, it's a dark brown precipitate that's formed into round loops, 
not unlike dead leaves in autumn. I now have the unenviable job of 
dismantling the tank and cleaning out the base and the air bubbler. One 
of these days I'll rig up a proper circulation pump and filter system 
(not unlike those on photo-lab machines if you've ever seen inside one 
of those)...

But anyway, back to the subject of my question. Does anyone know what 
this stuff is? My FeCl3 is a somewhat greenish brown at this point, but 
I've got a 5-litre bottle of "hyper-activated" FeCl3 in the garage. 
Would there be any benefit to adding a bit more concentrate to the 
working tank?

And the final question: how the hell do I get rid of this stuff? Flush 
it down the loo? Double-bag it and chuck it in the bin? Call a local 
haz-chem company who won't touch it until I've got some arbitrary number 
of litres of the stuff and am willing to pay several hundred quid in 
disposal fees?

Thanks,
-- 
Phil.
ygroups@...
http://www.philpem.me.uk/